89-91 mercury 60 hp

[Cajuncormier]

cant get my engine over 2-3 rpm while in the water. Runs great on muffs.

cleaned carbs 4 times
changed fuel pump and fuel filter
changed stator
changed coil packs
checked compression
checked timing

 

[GA_Boater]

Welcome aboard.

First thing is don't rev the motor high on muffs or you can cause damage because there is no load.

Second thing, did it used to run OK on the water or is it a new motor to you?

I see no mention of checking spark. Use a spark gap tester to make sure the juice is getting to the plug end of the wire.

What are the compression numbers? Is the gas fresh? Changed plugs?